Inelastic seismic design verification method for steel bridge piers using a damage index based hysteretic model

摘要

In order to ensure the safety of steel bridge piers against earth- quakes, their inelastic response up to collapse needs to be pre- dicted accurately. An evolutionary--degrading (E--D) hysteretic model was found to fulfill this need with very little computational effort. The model is based on a comprehensive damage index, which takes into account the effect of large deformation, low cycle fatigue and the nature of the loading history. Evaluation of the vari- ous structural parameters required to predict the seismic response of steel bridge piers is discussed and the formulas required are summarized. The accuracy of the method is illustrated by compar- ing the predicted response with that obtained from pseudodynamic tests using two accelerograms obtained from the Hyogoken- Nanbu earthquake of 17 January 1995 near Kobe City. The hyster- etic model is then used to predict the response of four hypothetical piers designed according to the Japan Road Association (JRA) code and it is shown that the resulting damage is a function of the natural period of the pier.